The demand for the administration of anesthesia during minimally invasive surgery, in which a surgical instrument is disposed in the patient's upper airway, such as the esophagus or the airway structures distal to the glottic opening, and a protective bite block is placed into the mouth opening, has created airway maintenance issues that were not routinely encountered when these procedures were conducted with low level sedation or no sedation at all.
After induction of an anesthetic, particularly intravenous general anesthesia, upper airway tone is relaxed to such an extent that the upper airway may be blocked, preventing the anesthetized patient from spontaneously breathing. Specifically, the tongue typically relaxes in such a manner as to block the flow of air into and out of the lungs. Thus the airway is not patent.
In an effort to overcome this upper airway relaxation and to ensure that an anesthetized patient continues to spontaneously breathe, mechanical rescue maneuvers are often employed. If successful, a mechanical maneuver, such as a jaw thrust or a chin lift, which entails lifting the patient's chin and extending the neck, may encourage the relaxed tongue to move into a position anterior and superior to the glottic opening, thus allowing the free movement of air during spontaneous ventilation. The jaw thrust and other mechanical rescue maneuvers, however, are frequently unsuccessful in establishing and maintaining a patent airway. Depending on the depth of the anesthetic employed, the combination of pharmacologic agents administered, and the size of the patient's tongue, these mechanical rescue maneuvers may not ensure that the patient's airway will be established, remain patent, and that the patient will be able to spontaneously breathe.
During minimally invasive surgery, such as esophagogastroduodenoscopy, transesophageal echocardiography, or bronchoscopy, in which a surgical instrument, including fiberoptic scopes or ultrasound probes, is disposed in the patient's upper airway, a protective bite block is placed into the mouth opening. Such a bite block is placed between the upper and lower teeth acting as a barrier preventing injury to the patient's dentition and damage to the surgical instrument. Typically, a tubular access hole in the middle of the protective bite block allows for the passage of a surgical instrument into the oral cavity. The bite block is placed into the patient's mouth opening before the induction of an anesthetic; during this time, the patient is conscious and able to follow commands such as to open and close the mouth. The bite block does not incorporate a tongue blade to displace the tongue away from the glottic opening, so the gag reflex is not initiated. If the gag reflex were initiated, the disposition of a surgical instrument would be significantly impeded and the procedure uncomfortable for the patient to endure. However, after a protective bite block is in place and the induction of anesthesia has commenced, an anesthetized patient's gag reflex is obtunded, and the patient is thus typically able to comfortably tolerate the disposition of a surgical instrument into the upper airway, including but not limited to the esophagus or the airway structures distal to the glottic opening.
During minimally invasive surgery, the relaxed tongue of an anesthetized patient may obstruct the movement of air into and out of the glottic opening. When this occurs, the jaw thrust or chin lift rescue maneuvers may be employed to displace the relaxed tongue and to reestablish a patent airway, thereby allowing for spontaneous patient ventilation. In the event that these rescue maneuvers do not provide for the reestablishment and maintenance of a patent airway, the minimally invasive surgery must be abandoned, necessitating the complete removal of the surgical instrument from the oral cavity. Further, in order to reestablish the patent airway, an airway device must be inserted into the oropharyngeal cavity to displace the tongue away from the glottic opening.
Oral airway devices designed for insertion into the oropharyngeal cavity to displace the relaxed tongue away from the glottic opening often may not used with a protective bite block and surgical instrument in place. During minimally invasive surgery, including esophagogastroduodenoscopy, transesophageal echocardiography, or bronchoscopy, a protective bite block is placed into the mouth opening, and a surgical instrument, such as a fiberoptic scope or ultrasound probe, is disposed in the patient's upper airway. Oral airway devices may not be used in such minimally invasive surgery, because they will not physically fit into the mouth opening while a protective bite block and a surgical instrument are in place.
Further, the insertion of said oral airway devices through a protective bite block is difficult and often impossible due to size incompatibility with the bite block. To force the insertion of a larger than compatible airway device may cause physical harm to the patient's dentition and oropharyngeal airway structures. In practice, these incompatible oral airway devices may only be inserted, after removal of the surgical instrument and bite block, either with the aid of a tongue depressor or an upside-down insertion maneuver and 180-degree rotation into a position that displaces the relaxed tongue superior and anterior to the glottic opening. If the bite block were left in place in the patient's mouth opening, the use of a tongue depressor would likely cause injury to the side of the patient's mouth, because there is limited space between the side of the mouth and the bite block. Alternatively, the 180-degree rotation method, with the bite block in place, would also be hazardous, as damage to the roof of the patient's mouth would likely occur. Thus, there is a need for an oropharyngeal airway capable of safe insertion, while both a bite block and a surgical instrument are in place, without risking damage to a patient's mouth surface, dentition, or upper airway structures.
Further, existing oral airway devices are generally constructed of non-recyclable and non-biodegradable materials and are disposed of after a single use. The demand for the administration of anesthesia during minimally invasive surgery, and the frequency with which it is performed creates a need for a recyclable and biodegradable oropharyngeal airway.
For the safe and environmentally friendly administration of anesthesia during minimally invasive surgery, including but not limited to an esophagogastroduodenoscopy, transesophageal echocardiography, or bronchoscopy, such that the procedure would not have to be abandoned in order to reestablish a patent airway, there is a need for an oropharyngeal airway device compatible with a protective bite block and preferably composed of a recyclable or biodegradable material, that will allow for the maintenance of a patent airway and spontaneous ventilation.